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                *      How to build a BLACK BOX     *

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                       (Also known as mute box)

To all who dare --

What is a BLACK BOX?   A BLACK BOX is a device that is hooked up to  your
fone that fixes your fone so that when you get a call, the caller doesn't
get charged for the call.  This is good for calls  up to 1/2 hour, after
1/2  hour the Fone Co.  gets suspicious, and then you can guess what happens.

The way it works:

What this little beauty does is keep the line voltage from dropping to 10v
when you answer your  fone.  The line is insted kept at 36v and it will make
the  fone think that it is still ringing while your talking.  The reason for
the 1/2 hour time limit is that the Fone CO. thinks that something is wrong
after 1/2 an hour of ringing.

All parts are available Radio Shack.  Using the least possible parts and
arangement, the cost is $0.98.  And that is parts for two of them!  Talk
about a deal!  If you want to splurge then you can get a small PC board,
and a switch.  There are two schematics for this box, one is for most normal
fones.  The second one is for fones that don't work with the first.  It was
made for use with a Bell Trimline touch tone fone.

        **  Schematic 1 for most fones  **

        **         LED ON: BOX ON       **         *Schematic was saved

   FROM    >--------------------GREEN->     TO     

   LINE      >--!   1.8k  LED  !---RED-->    FONE

                      !----/\/\/\----!>--!

                      !                      !

                      ------>/<-------

                            SPST

Parts:  1 1.8k 1/2 watt resistor

1 1.5v LED

1 SPST switch

You  may just have two wires which  you connect together for the switch.

      **  Schematic 2 for all fones  **

      **        LED ON: BOX OFF      **   *Schematic was saved

   FROM    >------------------GREEN->     TO

   LINE      >-------               ---RED-->    FONE

                            !    LED   !

                            -->/<--!>--

                            !               !

                              ---/\/\/---

                                1.8k

Parts:  1 1.8k 1/2 watt resistor

1 1.5v LED

1 DPST switch

Here is the PC board layout that I recommend  using.   It  is neat and  is very

easy to hook up.

 Schematic #1        Schematic #2

**************                       ****************

*                    *                      *  -------              *

* --<LED>---*                      *  !       !              *

* !                ! *                      *  ! <SWITCH> *

* Resistor   ! *                      *  ! !                 !  *

*                 ! ! *                     *  ! !                  /  *

* ------------- ! *                     *  ! !                  \  *

* !                 ! *                     *  ! <LED>!      /  *

* --Switch--  *                     *  !                   ! \  *

*  !               !  *                    *  !                    ! /  *

*  !               !  *                    *  !                    ! !  *

      <LOST IN TRANSMISSION>

Once you have hooked up all the parts, you must figure out what set of wires
go to the line and which go to the fone.   This is because of the fact that
LED's must be put in, in a certain direction.  Depending on which way you put
the LED is what controls what wires are for the line & fone.

How to find out:

Hook up the box in one direction using one set of wires for line and the
other for fone.

*NOTE*  For Model I switch should be OFF.

*NOTE*  For Model ][ switch  should  be
 set to side connecting the led.

Once you have hooked it up, then pick up the fone and see if the LED  is on.
If it is, the LED will be lit.  If is doesn't light then switch the wires and
try again.  Once you know which are which then label them.   *NOTE*  - If
neither directions worked then your switch was in the wrong position.  Now
lable the switch in its current position as BOX ON.

How to use it:

The purpose of this box is not to poeple who call you so it would  make
sence that it can only be used to receive calls.  When the box is  *ON*
then you may only recieve calls.  Your fone will ring like normal and the LED
on the box will flash.  If you answer the fone now, then the LED will light
and the caller will not be charged.  Hang up the fone after you are done
talking like normal.  You will not be able to get a dial-tone or call when
the box is on, so turn the box  *OFF*  for normal calls.  I don't recommend
that you leave it on all the time, as you don't want it to answer when Ma Bell
calls!

     The Lunatic Phringe BBS 

   312-965-3677 3/12/24 x100  Baud